1. Field of the Invention
The present invention relates to temporary guard rail systems disposed at the peripheral edge of a structure such as an elevated floor slab. More generally, the present invention relates to a clamping apparatus that can be used, inter alia, in the erection of such a temporary guard rail system.
2. Description of Prior Art
In the construction industry, commercial, industrial and multi-unit residential buildings are typically constructed with a framework of steel girders. The framework for the various floor levels as formed, concrete floor slabs are poured so that the workmen on the project have floor support upon which to perform their task. Since the floor slabs are poured before the building walls are constructed, it is important to create some type of perimeter guard at the edges of the floor slabs to prevent workers from inadvertently falling off the edge of a floor slab without realizing they are near the edge. Additionally, perimeter guard rails, to meet certain governmental standards, have to have a toe board that generally abuts the top surface of the slab so as to prevent tools and construction materials from falling off the edge of the slab onto workers below.
For many years temporary guard rails forming perimeter guards for floor slabs in a multi-story building or the like have been provided by installing temporary stanchions or posts at spaced intervals around the perimeter of an elevated floor slab. The posts or stanchions provide vertical supports to which horizontal guard rails can be attached to form the temporary guard rail around the perimeter of the floor slab.
Typical of systems used in constructing temporary guard rails or other perimeter guard constructions are those disclosed in U.S. Pat. Nos. 3,863,900; 3,995,833; 4,307,824; 5,029,670; 6,585,080; and 6,679,482.
In U.S. Pat. No. 5,560,588 there is disclosed a support for a temporary guard railing that comprises a base adapted to be removably attached to a floor surface, e.g., the surface of a slab, and support walls upstanding from the base and defining between them an inwardly opening socket for receipt of a post. At least one pair of parallel rail guide flanges are adjoined to the base and project laterally outwardly with respect to one of the support walls whereby a rail such as a 2×4 can be received between the rail guide flanges. The support disclosed in U.S. Pat. No. 5,560,588 has found wide-spread success in the construction industry, particularly, in use in forming temporary guard rails around wooden floors, stairs and the like. Further, while the support system disclosed in U.S. Pat. No. 5,560,588 can be employed with concrete slabs, stairs and the like, it suffers from the disadvantage that in such circumstances holes must be drilled into the concrete slab in order to mount the support. This is time consuming and furthermore requires, in many cases, that the drill holes be patched once the temporary guard rail system is removed.
Aside from erecting temporary guard rails along the peripheral edges of floor slabs, stairs and the like, clamp assemblies that can be used to clamp along the peripheral edge of a slab, stairs, or similar structure, have a wide variety of uses in addition to being used in the construction of a temporary guard rail.